part 01. Raumgeflüster
part 02. portable radio unit
Take an mp3 player, a UKW sending unit and a battery, put it into a snug little box and you have a portable FM radio station.
Lets start with the case.
I took the dimensions of all the parts that I needed to fit into the case. Namely one mp3 player, a 9V Battery and the transmitter. After I digitally arranged the components to my liking, I figured the size of the top and bottom piece of the case. I decided to go with round corners. A kerf bend allowed me to manufacture the side faces out of one piece, by making the material flexible where it needed to be.
I placed some holes to the one of the smaller sides of the box. This gives me access to the mp3 players on/off switch and the USB port. I also cut out a piece for the on/off switch of the transmitter.
I went to the workshop and used a laser to cut out all pieces according to my plans. I also cut out two frames with the outer diameter of the box. These helped me holding everything in place while gluing the bottom piece to the side face. If the side won’t really bend well, try wetting the outer side of the bends with water.
Attached to the top piece is a frame corresponding to the inner diameter of the box granting easy access to the box while holding the top on tight. I also cut out a little logo that I replaced with an equivalent out of opaque plexi glass.
The transmitter I used is the UKW-Oszillator B018. The possession or use of the transmitter might be regulated by law in your country. For me, I only need this to be a proof of concept. I left the sending unit unfunctional by not adding a coil to the circuit. After soldering everything else together, I added a power switch between battery and transmitter. I hooked up an indicator LED parallel to the sending unit.
So there you have it. A neatly encased, portable radio station. Whether you use it for a silent rave, for geocaching or to listen to your music while sitting in the garden, it really is up to you.
What I plan to with this, well that’s another story, for the next post…
This article helped me with the design.